U7137 ST Knock Log with Shell V-Power fuel

Harmwalker · Post by **Harmwalker** » Fri May 15, 2009 4:29 pm

Guys,

Take a look at this log and tell me what you think. I've ran logs before this instance using my normal fuel in the same conditions and I have never had this much knock in my truck. Pretty sure it's the V-Power. Take a look at the log notes and it explains where and how I drove. I'm going to run a few more logs with this tank and then go back to the fuel I usually use and log again to verify.

DiabloFan · Post by **DiabloFan** » Fri May 15, 2009 10:11 pm

Must be the nitrogen.

whitehemi · Post by **whitehemi** » Sat May 16, 2009 11:05 am

I used That gas on my trip to Sac and had very little KR and the truck loved it. I wonder why your truck doesn't like it?

catsltd · Post by **catsltd** » Sat May 16, 2009 12:48 pm

Im pretty sure you wont get knock like that at such low rpm,just from gas.
If you look when you accelerate the knock goes down,so i very much doubt its the gas.
Maybe bad injector???.
The knock seems to be random at cruising speed,thats what makes me think its something like bad coil,or injector.
You could try datalogging all 8 cycnlinders and see if you see something on any 1 cyclinder.

Harmwalker · Post by **Harmwalker** » Sun May 17, 2009 2:11 am

That does make sense. I'll try logging the cyln.'s and see what I can find. The low RPM knock at cruising speed was happening when the truck would engage the MDS. That is what you're seeing there. I have another log I want you guys to look at. It has to do with the same issue of the truck running at low RPM's except this time I'm at low speeds climbing a hill. I disabled the MDS to ensure that I could rule out that prospect and sure enough, when the engine started bogging down while climbing a gradual, semi-steep slope, the knock came back.

Take a look:

Harmwalker · Post by **Harmwalker** » Sun May 17, 2009 2:15 am

Johan,

If you could take a look at this stuff I would appreciate any feedback you might have. I'm thinking it is the Shell fuel but I won't know until I can fill back up with the fuel I use normally.

johan · Post by **johan** » Mon May 18, 2009 8:52 am

Was this done in a high load, high gear low rpm situation, ie. lugging the motor?
Looks like it was, in which case this is kind of normal.
To be sure i would do the same test with a different brand of fuel, and go to busy gas stations that circulate the fuel often.

snakejr · Post by **snakejr** » Tue May 19, 2009 1:30 pm

shell is shitty gas try chevron supreme

snakejr · Post by **snakejr** » Tue May 19, 2009 1:31 pm

shell is shitty gas try chevron supreme

electricmarquis · Post by **electricmarquis** » Tue May 19, 2009 4:02 pm

Johan is right.....this is engine lugging.

This is the exact same thing mine does. I have a 2007 4x4 as well. About 38-50mph in low rpm in high gear.....about 4th. This happens like clockwork. I use shell v-power, Sununco, etc. Its not the gas its the truck staying in 4th about 1400-1800 RPM and lugging about 45 mph.

The inital update to use Diablo changed the trans settings for partial throttle shifting to stay in 4th. The only way to stop the knock is to run premium fuel on the stock tune or to have a CMR done to alter the trans shifting pattern or lower closed loop timing in the 1400 rom range.

Most CMR guys will lower the timing because they dont like messing with the downshifting/tps settings for the trans.

Unforntuneatly using premium fuel on stock 89 tune will make your MPG go down, but you didnt buy the hemi truck at 5800lbs for mpg.

DiabloFan · Post by **DiabloFan** » Tue May 19, 2009 4:15 pm

Why not just put your 07 in od off when in town?

electricmarquis · Post by **electricmarquis** » Tue May 19, 2009 4:26 pm

Should have to, it was fine before the dodge update. Dodge prob changed it for EPA reasons.

Harmwalker · Post by **Harmwalker** » Thu May 21, 2009 1:30 pm

I do hit the OD off button in town to avoid the engine lugging knock. But it also happens on the highway. Here is another log to prove it.

Harmwalker · Post by **Harmwalker** » Thu May 21, 2009 1:32 pm

You guys are all saying this is pretty normal. Is there any danger to my engine with this going on? If so, it's probably not worth the CMR tune to get it to go away right?

Harmwalker · Post by **Harmwalker** » Thu May 21, 2009 1:34 pm

electricmarquis wrote:Johan is right.....this is engine lugging.

This is the exact same thing mine does. I have a 2007 4x4 as well. About 38-50mph in low rpm in high gear.....about 4th. This happens like clockwork. I use shell v-power, Sununco, etc. Its not the gas its the truck staying in 4th about 1400-1800 RPM and lugging about 45 mph.

The inital update to use Diablo changed the trans settings for partial throttle shifting to stay in 4th. The only way to stop the knock is to run premium fuel on the stock tune or to have a CMR done to alter the trans shifting pattern or lower closed loop timing in the 1400 rom range.

Most CMR guys will lower the timing because they dont like messing with the downshifting/tps settings for the trans.

Unforntuneatly using premium fuel on stock 89 tune will make your MPG go down, but you didnt buy the hemi truck at 5800lbs for mpg.

Sounds like getting some more shift parameters for 3-4 gears might help solve this problem?

U7137 ST Knock Log with Shell V-Power fuel

U7137 ST Knock Log with Shell V-Power fuel

RE: U7137 ST Knock Log with Shell V-Power fuel

RE: U7137 ST Knock Log with Shell V-Power fuel

RE: U7137 ST Knock Log with Shell V-Power fuel